Thermo-electric generator.



W. E. BRISTOL.

QHFJRMO ELECTRIC GENERATOR.

` APPLIOATION FILED DBO. 2. 1905.

HA 5 /l /3 ne. senese.

Specifxoetion of Letters Eetent.

etented Jan. i,

Appiicetion filed. Becembcr Z, 1905. Serial No. 280,017.

,Ton/ZZ .whom it may conce/rre:

Be it imovzn that i, Wimmer Beieren, e citizen of the United Stetes,enti e resident of New York, in the county oi' New York end State oi'New York, have invented certain. new end wech-i Improvements in Thermo-Eiectric Genere-tore, of which the .following is e specification. ,1,

`My invention hosieference to im' rovernents in thermo-electricgener'etors anepteci for use in pyrorneters, and reietes particuieriy toimprovements on the generetordis closed in my prior potent, No. Toer-77,oi July 5, 1904.

it hes for its object to compensate for the effects of changes oftemperature at the juno tion of the cheeper elements With the more exensive ones.`

`or this purpose my invention consists, essentieiy, of e thermo-eieotriogenerator comprising eienients oi' high using-points forming e. couple,elements of lower fusingpoints connected ,-to the elements of seidcoupie, and ineens adopted to compensate for the eeot of variations oi'temperature et seid junctions. i

'Heretofore it .hes been Proposed to join two eiements adoptedl toWitnstend. extremeiy high temperature with conductors less cepeble ofresisting temperature, but of greater conducting and lese expensive me-Yteriei, end to rneintein seid conductors et their junctions et ecomperetiveiy iow tempereture by Ineens ci e protective insulationsurrounded by'nv Weten-jacket or by so selectin 'the materiel orarranging the junctions of sci conductors so that the effects of thetemperature vcrietions upon the junctions will be neutralized. Theformer method is somewhat .cumbersome and imprecticebe and the letterdiiiicut of realization, because `oi the amount of experimental 'Workinvolved in the search for the combination of metals 'Which vi/iii'perfectly' eccolnpiish the desired results.

According to my present invention I epproznniete the generator disciosedin my prior potent, No. 754,177, end then ooinpiete the neutralizationof the effects or temperetur'efverietions upon the junction byprovidingsnitebie compense-ting ineens so arranged with. respect to thegenerator that the tern pereture verietions et thc junctions Will-noteectthe generator e.. Whole.

The' rieture of invention vriii be best understood :in connection. withthe eccompenyin'g'drewings, in which Figures 1 to e ere pis-n vic-Ws cimy iniproveci thermo-eiectric generator, showing the various ways ofarranging the cornpen:

Asetting Ineens.

Similar nnmeres of reference designate corresponding parts throughoutthe severe-1 views. Y

Referrino now to the cirewings, l end 2 designete tahe elements oi otherrnwelectric coupe joined together et 3 in the usuari manner. Thiscoupie is composed of nietas or cioys heving high fnsinpoints andcepebie of resisting extrerneiy high temperatures Without re ifideterioration-essen, .for l effigie, es p etinum and en aiioy of)ietinuni ten per cent. of rhodium. it is iv'eii known that thesemateriels ere possessed of comparatively high resistance and ere veryexpensive. To reduce the cost and the resistance of the generator es oWhole, Ineke use of the elements 4 and 5 of e material or nisteriaiswhich are comparative-1y inox-- pensive substances-for exemple, iron,steel, nickel, or eiloys thereof-end which have e.

lower fusing-point than the seid expensive' elements. Qwing to theinexpensiveness of the elements 4 and 5, they nley `therefore be mede ofsuch proportions that they xviii offer but iittie'resistence to theposseggo of' the cofrrent and their resistance be inopprcciebiyaffected, by tempera-ture variations.V

The elements 4 end 5 ere so for removed.

from the fire end 3 of thecouple that they do not receive the i'nllheet, but only radio1-ed or conducted hee-t, and ere therefore notsubject to injury from the intense heet te which the expensive elementsare subjected, the junctions being et the points 6 and 7.?,

In view of the feet that different nieta-is or metals and alloys meet etthe junctions 6 and- 7 secondary couples ere formed, `Whose com binedeffect is to produce e current opposing or increasing the currentdeveioped by the ther1no-e1e`ctrc generator. As indicated by the arrowsin Figs. vi end 2, the combined. .eiect of the secondary currents is toincrease the current produced by thc ther1no-e1ectric generator, Whilein Figs. 3 and 4 the cornbined effect j of the vsecondery current isshown to oppose the current of the generetor. To compensate for thesecondary effect et the junctions end 7, il eroi/"1de e suitebiercestencs 3, either in seri s or in perrege allel with said generatorand located in close proximity to the said junctions, By these means iam enabled to compensate for or neutralize the effects due to thetemperature variations upon the junctions 6 and 7 For example, as shownin Figs. l and 2, the tendency of the secondary effects is to increasethe total effect of the generator with an increase of temperature at thejunctions 6 and 7. To obviate this, l place the resistance 8 withpositive resistance coefficient in series with one of the elements 4 and5 or the elements 1 and 2, thereby affecting the generator as a whole.Being located in close proximity to the junctions 6 and 7,thisresistance will be increased'with an increase of temperature and isso calculated as to cut down Athe effect of the generator as a whole inthe same proportion as the combined secondary effects of the junction orsecondary couples would increase it'. l thus maintain a correctdevelopment ol current by th generator as a Whole, depending solely upoithe difference in temperature between the fire end 3 and the cold end 9.

The elements et and 5 are au active part of the generator a whole,having its fire end at 3 and its cold end at E), and any thermoelectriceffect isdependent solely upon dif"- ferences of temperature between.these two points, variations of temperature intermediate of these pointshaving no e'ect u pon the generator.

As shown in Figs. 3 and 4, the tendency of." th.e combined secondarythern'io-electric ef"- fects is to oppose or decrease the thermojelectric effect of the generator with increase of temperature at thejunctions 6 and 7. l therefore pl ce the resistance 8 of" positiveresistance coefficient. in parallel with the genj erator as a whole,sliownio Figs. b and 4.

Then as the temperature increases at the `junctions t5 and 7 thisresistance will also increase and will short-circuit less oll thecurrent developed by the gmlerator, thereby increasing the effect of thegenerator asa whole. The resistance H isl so calculated as to increasethe active efl'eet of the generator in the same proportion as thecombined secondary effects ofl the junction or secondary couples woulddecrease it, thereby maintaining a correct current for the generator as'a whole, irrespective of the temperature variations at posit ionsintermediate of its fire end 3 and cold end t),

lt is obvious that l may employ resistances having negative temperaturecoefficients and arrange them accordingly; but fl' prefer to use aresistance. having tcn'iperatnre coefficient.

The generator is provided with terminals 10 and l1. and leads l2 and l,which are adapted to be connected to the usual indieating or recordingdevices to indicate or rca positive cord the thermo-'electric efiect ofsaid generator.

What I claim as new, and desire to secure by United States LettersPatent, is-

1. A thermo-electric generator compnsing: primary elements of highfusing-points forming a couple g secondary elements of lowerfusing-points connected thereto and forming secondary couplesintermediate of the hot and cold ends of said generator; and meansindependent of said elements adapted to compensate 'for the effects ofsaid secondary couples.

2. A thermo-electric generator comprising: primary elements of platinumand an allo y of" platinum with. ten per cent. of rhodium, forming acouple; secondary elements of nickel-steel alloy and of iron,respectively connected thereto and forming secondary couplesintermediate ofE the hot and cold end of said generator and meansindependent of said elements adapted to compensate for the effects ofzsaid secondary couples.

3. A thermo-electric generator comprising: primary elements of highfusing-points forming a couple, secondary elements of lowerfusing-points connected thereto and forming secondary couplesintermediate of the het and cold end of said generator; and a resistancelocated in close proximity to the junctions of said secondary'elementswith the said primary elements, and adapted to compensate for theeffects of said secondary couples.

4. A thermo-electric generator comprising; primary elements of platinumand an alloy of" platinum with ten percent. rhodium, forming a couple;secondary elements of nickel-steel alloy and of iron, respectivelyconnected thereto and forming secondary couples interim-,diate of thehot and cold end of" said generator g and a resistance located in closeproximity to the junctions of said secondary elements with the saidprimary elements, and adapted to compensate for the ef-.

feets of the said primary couples.

5. A thernio-electric generator comprising: elementsol highfusing-points forming a couple; secondary elements of lower fusing-.pomts connected thereto and forming secondary couples intermediate ofthe hot and cold end of said generator; and a resistance located inseries with said generator and in close proximity to the junctions ofsaid secondary elements with said primary elements, and adapted tocompensate for the effects of said secondary couples.

6. A thermo-electric generator comprising: primary elements of platinumand an alloy ot'` platinum with ten per cent. rhodium, forming a couple;secondary elements of nickel-steel alloy and of iron, respectivelyconnected thereto and forming 'secondary couples intermediate of the hotand cold end IIO lIq

' Vments Withseid ed to compensate for the effects of said secondarycouples.

Signed et New York city, in the county of New York and State of NewYork, this 29th day of November, A. D. 1905.

WILLIAM H. BRISTOL.

Witnesses:

FREDK.' F. ScHUETz, SALLYE O. YUDIzKY.

